Anemia can be treated by enhancing the production of or replacing or enhancing levels of red blood cells. Anemia may be chronic or acute. Chronic anemia may be caused by extrinsic red blood cell abnormalities, intrinsic abnormalities or impaired production of red blood cells. Extrinsic or extra-corpuscular abnormalities include antibody-mediated disorders such as transfusion reactions and erythroblastosis, mechanical trauma to red cells such as micro-angiopathic hemolytic anemias, thrombotic thrombocytopenic purpura and disseminated intravascular coagulation. Infections by parasites such as Plasmodium, chemical injuries from, for example, lead poisoning, and sequestration in the mononuclear system such as by hypersplenism can result in red blood cell disorders and deficiencies.
Generation of erythrocytes from embryonic stem (ES) cell-based approaches is limited by scalability and limited methodology for generating erythrocyte progenitors. Although previous technologies have used bone marrow and cord blood hematopoictic stem cells, useable production of erythroid progenitors has not been achieved. Conversely, technologies exist for terminal differentiation and enucleation of erythroid progenitors, however, production of ample amounts of the “starting cells” has not been successful.